Internal combustion hammer



Dec. 7, 193 7.

E. R. BoDDlNGHoUsE INTERNAL COMBUST ION HAMMER Filed Aug. 13, 1954 v3Sheets-Sheet l EmnwIwRodcmg/wwe,

Dec. 7, 1937. E. R. BODDINGHOUSE V2,101,608

INTERNAL COMBUSTION HAMMER Filed Aug. l5, 1934 3 Sheets-Sheet 2 Dec. 7,1937. E. R. BODDINGHOUSE 2,101,608'

INTERNAL COMBUS TION HAMMER Filed Aug. l5, 1934 3 Sheets-Sheet 3 *f |nwww.

t .i [mgm nlll a nl: lllllll II Emmons R. Boddinghc c i I alertesnetrunner. oo L r hlco. Iii., assigner to Gas 'llool Patents orpotion,Chicago, lill., a corporation of Delaware.

Application August i3,

9 Claims.

This invention relates to improvements in internal combustion hammers.

One of the objects oi the invention is to provide a portable internalcombustion hammer so constructed that the conduction of heat from thecombustion chamberto the associated parts oi the device is limited andcontrolled for minimizing the harmful effect of such heat upon theassociated parts.

Another object of the invention is to provide a hammer having such apredetermined relationship between the relative weightsmf the parts, thespring load and the hardness of the parts as will ensure durability andmost emcient operation. Another object of the invention is to provideimprovements in the cooling in construction affordingmore rapiddissipation of heat and greater strength in the entire device.

Another object of the invention is to provide a construction assuringthe device greater ruggedness and durability.

Other objects and advantages of the invention inherently possessed by itwill become apparen upon a perusal of this specication. Y Y

in the drawings:

Fig. l is a vertical axial section through a device embodying theinvention;

Fig. 2 is a plan view oi the device;

Fig. 3 is a detail view in cross section through the cylinder and pistonin the plane indicated at 3--3 in Fig. l;

Fig. 4 is a side elevation of the device from viewpoint ninety degreesremoved angularly from that of Fig. l, a portion of the fuel tank andcarburetor being broken away in section;o

Fig. 5 is an enlarged fragmentary detail in section through a portion ofthe fuel tank'and carburetor; i

Fig. 6 is an enlarged fragmentary detail in section in adifferent planefrom the section of Fig. 5 showing the carbureton'mixing valve;

Fig. '7 is a bottom plan view'ot the f uel tank and carburetor unit; y

Fig. 8 isa side elevation, partly in section, showing a modified form ofmy invention; and Fig.

9 is an enlarged view showing the abutting relation of the return andcushioning springs.

The cylinder t is provided with cooling ns t which preferably extend invertical planes-radiatresi, semi no. '139.553 (on. ics-'1) against oneof the ilat surfaces on the spark plug li will serve to prevent thespark plug from becoming unscrewed.

The castings employed in this device, with the exception of the cylindercasting, are preferably made of steel.

at the top or the unsA o there is provided an annular shoulder it uponwhich rests a handle ring ld to which the handles lll are bolted. One ofthese handles serves as a conduit to receive the cable l5 which carriesthe electrical connections to the spark plug ll and the timerhereinafter to be described.'

The connectionv between the handles and the handle ring i3 is preferablyeffected through a heavy gasket it which isulates the handles from theheat developed in the-cylinder casting. The

joint between the cylinder casting and the handleI ring, although notprovided with any gasket, -isl 4in itself a means of heat insulationsince -any joint odors a high reluctance path to -the con-v ductance ciheat.

^ .lit the lower end of the cylinder casting is-the sro-called lowerunit ll which closes the lower end of the cylinder and provides abearing guide for theanvil member lt, into the socketed end of whichfthetool ld is received. The tool is guided .in a htting it applied to thelower unit ll. Packing rings it surrounding the anvil it serve toprevent escape of gases downwardly from the sub-piston compressionchamber 2t.

lt is important to note the location of the joint between the lower unitll and the cylinder casting. This joint is located relatively high onthe haer and is packed with a gasket llla to minimize heat conductionfrom the cylinder to the iuel ta and carburetor unit, which is supportedfrom the lower unit ll in a', manner hereinafter tovhe described.

Thehandlering,cylindercasting,lower unit and tool guide are held inassembled relationship by -means of long tension bolts il. Annular4shoulders il, above which these bolts are reduced in diameter, inconnection with nuts t ia lrmly seat the unit lll against the bottom ofthe cylinder. A dat surface tl on each bolt fitting into correspondingrecesses in the unit lll prevent these bolts from turning. Surrounding.the lower ends oi the tension bolts are heavy dsprings 22 seated uponheads tit and 2t and against the tool l Just below the nuts tia thetension bolts are provided with reduced portions 2id having diametersapproximately one-half that of the lower com ci the lts. By reason ofthe presence of these reduced portions it is found that when thecylinder casting expands, due to heat during operation of the hammer,these bolts will stretch, particularly in the reduced portions 2id, andwill return to their original length when the casting becomes cool. Thusthe unit I1 and ring I3 will always be held seated very firmly upon thecylinder casting.

When the tool or drill I9 is engaged with the work and the weight of theentire device rests upon it, the anvil I8 will be supported free fromthe bottom 25 of the recess in the tool guide. The tool guide itselfwill absorb the impact of the piston whenever the work does not absorbit through the tool I9. The resistance, offered by Ithe tool guide tothe impact of the hammer under such conditions may be varied bysubstituting stronger or weaker springs 22.

'Ihe timer for producing the spark is housed in a sleeve 21 insertedinto the cylinder casting and carries a reciprocable piston 28 ontheinner end'of which is mounted a cam follower roller 29. On the outer endof this piston is positioned a spring 3l seated against a shoulder onthe plate 32 for holding the cam follower 29 against its associated cam.The upper end of the contact spring is insulated from the hammer bybeing clamped between two insulating washers, as shown. The lower end ofcontact 33 normally rests against a post 34 made of insulating material.A camsurface 35 is provided along the skirt of the piston 36.

When the timer piston 28 is moved outwardly by the cam 35 it strikes thespring 33 and grounds it on the frame ofthe hammer, whereupon theignition spark is created.

" jected.

The upper end of the piston is provided with a plurality of horizontalpassages 39 which communicate with a recess 4I at one side of thepiston. At the lower end of the downstroke of ber 42. At that instantcommunication is established between the combustion chamber 43 and thesub-piston compression chamber 28. The described communication iscompleted through the horizontal passages 39 and a plurality of verticalpassages 44 disposed as shown.

The return spring 45 and the cushioning spring 46 are preferably woundin the same direction and have square ends which abut each otherslightly below the top of the reduced portion of the anvil I8 as shownin Fig. 9.

Mounted on top of the device and extending downwardly through the top ofthe upper casting is a plunger 41 having an enlarged head 48 and a smallhead 49 at its lower end .which extends into the top of the combustionchamber. A spring 5|. resting upon the top of the casting and againstthe head 48, as shown, normally maintains this plunger in raisedposition. The plunger is employed for thrusting the piston downwardlywhen it is desired to start theA piston in operation. By locating thespring 5I on top of the fins rather than upon the top of the combustionchamber it is thus separated from the of the piston. check valve 59which is normally held seated by a cylinder sufficiently to be shieldedfrom temperatures that might adversely affect its temper.

The fuel tank which supplies the fuel for the combustible mixture iscarried upon the device, extending part of uthe distance around the sideof the device. The tank, designated 52, is supported wholly upon thelower unit I1 of the apparatus, and by reason of its location low on thedevice and because of the gasket |13 opposing downward conduction ofheat, the fuel tank is found to be sufficiently shielded from heatproduced by operation of the hammer to avoid any harmful evaporation ofthe liquid fuel carried in the tank. The gasket I1a and the jeint inwhich it is disposed together serve as a very efficient combined heatinsulator. The lower unit is provided with a boss 53 upon which isfitted an appropriately shaped part 54 of the fuel tank. Bolts 55 serveto firmly unite the tank to the boss 53. A U-bolt 56 connected with thefuel tank and embracingthe sides of the device, as shown, assists insecuring the tank in position. Carried byand partially contained withinthe fuel tank is a carbureting device which includes a screened airinlet 51 opening into a passage 58 for admitting air under suctioncreated in the sub-piston compression space during the upstroke The airis admitted through a spring 6I. Suction lifts the valve 59 and as theair flows past it a charge of liquid fuel is drawn through a strainer 62positioned within the bottom of the fuel tank through a passage 63 pasta needle valve 64, thence through the regulating nozzle 65 into the airstream. The combustible mixture then flows into the passage 66, thenceinto a vertically extending recess 61 in the unit I1 adjoining thereturn spring 45. This recess delivers the combustible mixture into thesubpiston compression space wherein it is compressed on the downstrokeof the piston and thereafter transferred through the transfer chamber 42upwardly into the combustion space 43 at the time the piston reaches thelower limit f its travel. The recess 61 cut back into the cylindricalpassage in the lower unit I1 prevents the convolutions of the springsfrom interfering with the travel of this gas. Q

It is ,particularly worthy of note that the valve 59 and its mountingand the needle valve 64, its mounting and the strainer intake. 62 areunitarily mounted in a block 68, which is removable and replaceable as aunit and which when secured to the bottom of the fuel tank constitutes aunit with the fuel tank whereby the composite unit may readily beremoved from the device and replaced. A cover 69 (see Fig. 5) isemployed to surround the lower end of the valve 59.

The vertically extending heat radiating fins 9 add considerable strengthto the entire device Without unnecessarily increasing the weightthereof. Vertical channels between these vanes enable the heated air torise and escape readily. The handle supporting ring being mounted at thetop of these vanes and having apertures therethrough, as shown in Fig.1, is itself maintained fairly cool. The plunger supporting spring Ibeing supported above() the rest of the structure adornos am sides oi'the cylinder casting, is a further aid in saving the fuel tank frombecoming too hot.

A cover Il for the filling opening for the fuel tank is provided, asshown.

For returning the piston it is preferred to use the combined action ofthe springs d and tt' although one spring alone or more than two springsmight be used.

The battery and coil for supplying the ignition current will beconnected with the cable l5 Aand supported either apart from the hammeror upon it. o I

By delivering the freshly formed fuel mixture into the lower end of thecylindrical channel in the unit' il, the adjoining portions of thesprings are cooled and their heat is thereby carried away by thecombustion charge. 'Ihe channel l'l is provided to prevent these springsfrom blocking the ecient delivery of the fuel but ould not be so wide asto permit the springs to enter thereinto. The upper end of the returnspring is cooled by the-gases owing into the vertical passages tt, whilethe remainder of this spring is exposed to cooling by the gases in themiddle portion of the sub-piston compression space.

In the operation of the device the piston is 4returned after the powerstroke by the combined action of the springs t5 and dt and the reboundwhich occurs from the impact of the striker por- `tion of the pistonupon the reduced portion of the anvil.l In order that the anvil andhammer may have the necessary durability and may cause the desiredrebound, they should each have aV minimum hardness of 60 scleroscope.

The maximum A"spring load referred to herein is that force in poundsrequired to force the piston manually down into contact with the anvil.

I have discovered that the maintenance of a predetermined ratio betweenthe piston weight, the scleroscope hardness of the striker portion oithe piston and of the anvil, and the maximum spring load of the returnsprings is essential to efiicient operation of the hammer as a whole.rIhe scleroscope hardness of the striker portion till and the anvilpreferably should, not fall below` a minimum of 60 scleroscope. "Themamirn'umD spring load in pounds of the return springs should not exceedthirty times the weight in pounds of the piston. When-these ratios aremaintained, the device will have the rapidity of action required for itswork and excessive vibration will not be imparted to the entire device.

While the piston is shown as comprised 'of two parts assembledpermanently together, it is contemplated that the striker portion may beoriginally cast or otherwise formed integrally with f the upper portionof the piston.

Fig. 8 shows a modified form of my invention which has the same internaloperating parts as the preferred form shown in Fig. l, but involves adifferent external assembly of the cylinder, the

anvil housing and the handles. In the modiiied form' the lower end ofthe cylinder is clamped directly to the upper end oi the anvil housingwhile the handle ring is supported wholly on the long outside tensionbolts rather than upon the cylinder fins. This modied form of theharnmer comprises a cylinder tl on the. outer surface of which is aplurality of outwardly and longitudinally extending iins t2. The upperends of these fins are formed as shown to pass within a handle ring t3,this ring not being supported upon the iins but merely lightlycontacting the edges thereof. ahamd `and construe .-r te..

ring of Fig. l, ving insulating strips ad and handles tt.

At opposite sides the handle ring is provided with lugs, one of which teis shown, through which the outside tgnsion bolts pass. The bolt tl,shown in Fig. 8, is provided with a shoulder just below the lug, uponwhich the lug seats, and

a nut te clamps the two together. The lower end of the tension bolt lextends through the flange t@ on the cylinder casting and through thewall of the anvil housing or lower unit 9i. It will be understood that apiston and an anvil, together with return springs similar 'to thoseshown in Fig. 1, are employed in this modled form of the invention. 'Iherod tl extends upwardly through the lower unit 9i, passing into a bossQ2 at which point is located a shoulder 93 on the rod, together with acorresponding recess in. the lower unit and a flat surface 9d on theside of the rod cooperating with a corresponding iiat sided recess toprevent turning oi the tension bolt. A pin 90 may be driven through eachbolt @l just above the ange t9 to prevent downward movement oi the bolt.

A tool'guide t5 is yieldably supported on the tension bolt tl and itsmate on the opposite side, as in the preferred embent. One of thecompression springs @t is shown resting.

against the nut @I and a bossld on the tool guide.

In order to secure the cylinder casting and the lower unit iirmolytogether without undue conduction of heat from the cylinder to the anvilhousing, I have provided a pair of bosses 9B and 99 at the lowermarginal portion of the cylinder casting and cooperating bosses itl anditi on the anvil housing. Short bolts itt and ltd passing through thesebosses secure the two parts iirmly together. A heat insulating gasketidd at the juncture of these two parts prevents any un-` duly extensiveconduction of heat from the cy l' inder casting to the anvil housing.This precaution is important in order that the fuel tank, which issupported Wholly on the anvil housing,

as is the case in the preferred embodiment, may

be protected from the heat generated by the operation of the hammer. Thelower end of the cylinder, where the lugs are lcatel', naturally is keptrelatively cool by reason of the iuel mixture flowing through thesub-piston compression space within the lower end oi the cylinder.

During use the cylinder casting will become heated and will naturallylengthen but this tendency to lengthen is not in any way restricted bythe handle ring, as the iins may" slide upwardly therewithin and returnequally easily when cooling. 'I'here is, therefore, no increase ordecrease of tension upon the tension bolt tl and its counterpart on theother side of the hammer by reason of expansion or contraction of thecylinder. Therefore the reduction in area of the tension.v bolts, asshown in Fig. 4, is not neces-v sary in this embodiment. In fact, thesetension bolts may well he made much Ymore sturdy as they must sustainwholly or nearly so thethrust imparted 'between the lower end of thehammer and its handles.

It should be understood that the constructions herein shown anddescribed have been selected for the purpose of illustrating theinvention, and not for the purpose of indicating its limits. Variousmodifications of the invention and its parts may be made without adeparture from the scope of the invention, particularly as it is deed inthe appended www ing a cylinder and cooling ns thereon extendingoutwardly therefrom longitudinally of the cylinder to a point above thecylinder, an anvil, an anvil housing below the cylinder, a tool guidebelow said housing, a handle ring seated upon the upper ends of saidfins above the cylinder and constructed to permit air circulationtherethrough between the ns. and means cooperating with said ring andtool guide for retaining said ring, cylinder, anvil housing, and toolguide in assembled relation.

3. The combination of a cylinder and a spring returned piston therein, aseparable lower unit seated against the lower end-of said cylinder andinsulated therefrom, a fuel` tank supported on said unit and an anvilcarried by the unit, a tool guide seated against the inner side of theunit for receiving impact from the anvil and yieldable thereunder awayfrom said unit, cooling fins on said cylinder extending outwardlytherefrom longitudinally of the cylinder and extending thereabove, ahandle ring supported on the top of said fins near their outerextremities so as to permit clrculation'of air between said iins andthrough said ring, and means cooperating with said ring for rigidlysupporting said unit and yieldably supporting said tool guide.

4. In an internal combustion hammer having a cylinder and a springreturn piston therein, an anvil housing at the lower end of saidcylinder, heat insulating means disposed between said cylinder andhousing, radiating iins on the cylinder projecting radially therefromand' extending longitudinally thereof above the upper end' of saidcylinder, a handle supporting member mounted upon the top of said finsnear the outer extremities thereof so as to permit air flow through saidmember, a tool guide below said housing, and means connected to saidmember ior rigidly supporting said housing upon the cylinder andyieldably urging the said tool guides against the lower end .of saidhousing.

5. An internal combustion hammer comprising a cylinder, a pistonreciprocable therein, radially disposed ilns extending longitudinally`of said cylinder and beyond the upper end thereof, asplunger rod guidelocated above the cylinder and coaxially therewith, the upper ends ofthe spacesl between the fins being open to provide for air circulationaround the cylinder and guide, a plunger. rod extending through saidguide and the cylinder head `and having at its upper end provision forhand operation of the rod, and a spring interposed between the upperends of said fins and the hand provision on the rod whereby said rod isyieldably retained in raised position.

6. An internal combustion hammer comprising a cylinder, a springreturned piston reciprocable therein, cooling fins extending radiallyfrom the cylinder and projecting longitudinally thereof above the upperend of the cylinder, a starting plunger extending from within thecylinder to a position above the top of said fins, a plunger guidedisposed axially of said cylinder at the upper end of the iins, a handlering disposed circumferentially of the fins at their upper ends so as toleave unobstructed air passages defined by said fins, said guide andsaid ring, and a spring mounted above said fins in the path of said airflow for holding said plunger in raised position.

'1. An internal combustion hammer comprising a cylinder provided withcooling fins extending radially outwardly therefrom and projectinglongitudinally of the cylinder above the upper end thereof, handlesupporting means, and a plunger guide carried by said fins above saidcylinder and constructed to afford unobstructed passages between said nsto facilitate unrestricted upward flow of air between said fins. A

8. An internal combustion hammer comprising a cylinder equipped withradially projecting longitudinal disposed radiating iins extending abovethe upper end of the cylinder, an anvil housing at the lower end of saidcylinder, a tool guide abutting the lower end of said housing, a handlering seated upon the upper ends of said ns, tie rods extending betweenadjacent fins and through said ring, said housing, and said tool guide,said rods having shoulders engaging said housing and nuts threadedthereon above said ring whereby said ring, cylinder, and housing arerigidly clamped together, said rods being of .re-

duced diameter adjacent to the cylinder to facilitate longitudinalexpansion and contraction thereof in conformity with variations in thecylinder length whereby rigidity of the assembly is maintained withoutinjury to the said rods,vand springs interposed between the headed lowerends of said rods and said tool guide to yieldably hold said guidesagainst said housing.

9. An internal combustion hammer comprising

